New treatment options for diffuse diabetic macular edema

WHO reports let assume that 180 million people suffer from diabetes worldwide. Diabetic macular edema is the most common cause of visual deterioration in these patients. Factors for the development of a diabetic macular edema are the duration of the disease, age at onset and general factors, which give evidence for the heaviness of the disease. Focal macular edema responds well to focal laser treatment whereas diffuse edema often persists despite modified grid laser treatment. For these eyes several new treatment options were evaluated during the last years. Since OCT investigations became more and more popular the role of the vitreous was of main interest. A thickened posterior hyloid was recognized as a diffusion barrier and cause of possible traction on the central retina. Numerous studies showed a visual increase and a decrease of the retinal thickness after vitrectomy in these patients. Intravitreal injections of triamcinolone acetonide seemed to displace surgical interventions. Several authors report of distinct improvements after intravitreal application of 4 mg. However, major problems are secondary glaucoma up to 68%, secondary cataract development and the need for repeated injections due to a 3-months clearance of the substance in non-vitrectomized eyes. To avoid these complications long term sustain released systems with steroids which are implanted via the pars plana were described recently. New options are intravitreal anti-VEGF therapies. Promising reports with 3 different products (bevacizumab, ranibizumab and pegabtanib) show a good effectiveness for patients with diabetic macular edema. These studies are still running. Last but not least there are new systemic options (PKC beta inhibitors, somatostatin) under investigation. These substances are taken orally and could influence the progression of diabetic changes but not cure a diabetic edema so far.